The disclosures herein relate generally to a computer system and more particularly to retention of a heat sink for cooling the computer system.
As the speed of computer microprocessors continues to increase, the heat that they are generating increases. Heat dissipating bodies such as heat sinks are often used to cool microprocessors. Faster processors are requiring larger, heavier heat sinks whose weight can cause the computer board to bend and flex when the heat sink is mounted to the board and when the board is subject to shock and vibrations while mounted to the computer chassis. Flexing of the computer board can be extremely damaging to the traces and components on the board.
Increased processor power has demanded heavier heat sinks and stronger heat sink clips and fasteners. Presently used clips require a large amount of force to open and close. In addition, if a clip is incorrectly installed, damage to the motherboard may result.
The use of higher force clips causes ergonomic issues for manufacturing personnel. As a result, an installation tool may be needed to supply a needed mechanical advantage. This can create a problem for field service repair needing the tool for removal and replacement.
In order to preserve contact between the processor and the heat sink, some clips create a large amount of preload force.
One approach has used metal leaf springs placed on each side of the heat sink and attached to a plastic base. This approach creates an accessibility issue inside the chassis creating multiple areas that need to be accessed in order to assemble and disassemble the heat sink.
Another approach is a metal clip that spans across the middle of the heat sink and attaches to the socket. This creates a single contact area on the sink which permits the sink to wobble. This approach is no longer feasible because the newer sockets are too small.
Therefore, what is needed is a heat sink retention apparatus which provides sufficient retention during shock events, and which provides an optional thermal interface between the heat sink and a processor with which the heat sink is engaged.
One embodiment, accordingly, provides a torsionally originated force to retain a heat sink. To this end, a frame has a first end and a second end. A rotatable shaft is mounted on the frame. A heat sink retention arm is provided on the shaft and is rotatable with the shaft between a lock position and an unlock position. A driven member is provided on the shaft. The driven member includes a slot and a plurality of grooves. A rotatable driving member is mounted on the frame adjacent the driven member. A tab on the driving member engages the slot for rotating the driven member in response to rotation of the driving member. A plurality of arcuate members on the driving member engage the grooves in response to rotation of the driving member. As a result, the retention arm is movable between the lock position and the unlock position.
A principal advantage of this embodiment is advantage of this embodiment is reduced manufacturing time and easy access for repair or replacement. The torsion spring also provides a preload on the processor socket and limits tolerance stack-up of the processor.